IOP Conference Series: Earth and Environmental Science

Conductivity (EC) and total dissolved solids (TDS) are water quality parameters, which are used to describe salinity level. These two parameters are correlated and usually expressed by a simple equation: TDS = k EC (in 25 °C). The process of obtaining TDS from water sample is more complex than that of EC. Meanwhile, TDS analysis is very important because it can illustrate groundwater quality, particularly in understanding the effect of seawater intrusion better than EC analysis. These conditions make research in revealing TDS/EC ratios interesting to do. By finding the ratio value, TDS concentration can be measured easily from EC value. However, the ratio cannot be defined easily. Previous research results have found that the correlation between TDS and EC are not always linear. The ratio is not only strongly influenced by salinity contents, but also by materials contents. Furthermore, the analysis of TDS concentration from EC value can be used to give an overview of water quality. For more precision, TDS concentrations need to be analyzed using the gravimetric method in the laboratory.

In this paper, we examine existing literature on the way that the number of blades of a wind turbine affects its efficiency and power generation. A wind turbine blade is an important component of a clean energy system because of its ability to capture energy from the wind. The power that a wind turbine extracts from the wind is directly proportional to the swept area of the blades; consequently, the blades have a direct effect on power generation. The number and configuration of the blades is very important because it affects the speed and efficiency of turbine. Unfortunately, as the number of blades increases, so does the slipstream effect. Too few a number of blades results in poor efficiency and thus inadequate performance. Too large a number of blades increases weight and production cost. The correct number of blades is important to fit the generator performance curve to optimize overall turbine performance and efficiency.

Tesla's rapid rise to become one of the world's most influential automakers has marked the start of a new era in the global automobile industry, where many of the traditional auto companies were overshadowed by Tesla's dominance. Judging from Politics, Economy, Society and Technology perspectives, Tesla's market value can potentially be overvalued due to its leading role in the Electrical vehicle market. Economically, Tesla facilities the growth of global economy by creating more employments and manufacturing factories. Socially and politically, Tesla's Electrical Vehicle reduces the level of negative externalities (e.g., pollution), which aligns with the developmental frameworks proposed by governmental policies and regulations. Meanwhile in technological aspect, Tesla pioneers the innovative design of battery pack to reduce the overall cost of battery and seeks to integrate better automatic driving system into electrical vehicle. Given those merits of Tesla, overoptimism on its stock price is expected. Therefore, it is important for stock traders who are willing to throw money at Tesla to ruminate over their choices before making the investment. In this study, the results of valuation methods indicate that true market value of Tesla has been overestimated due to its irregularly high operating cash flow, price-to-earnings ratio and enterprise value to earnings before interest, taxes, depreciation, and amortization ratio, suggesting its stock price is overvalued.

Katuk is widely popular with its benefits for breastfeeding mothers. Katuk is also known as a plant with a high antioxidant content. This study aims to determine the effect of using variations in the ethanol concentration as an extracting solvent in producing Total Phenolics Content (TPC) and Total Flavonoids Content (TFC) and their activities in reducing DPPH free radicals. The dried katuk leaves were extracted by cold maceration method. The solvent used for extraction is ethanol with 3 variations in concentration: 50%, 70%, and 96% (absolute ethanol). TPC and TFC were determined by colorimetric method using a UV-Vis spectrophotometer. TPC was stated to be equivalent to gallic acid, while TFC was stated to be equivalent to quercetin. DPPH free radical scavenging activity was measured based on the IC50 value. The results showed that Katuk leaf extract produced from 50% ethanol solvent was able to produce TPC (42.18 ± 0.30 mg GAE / g), TFC (11.18 ± 0.38 mg QE / g) and reduction activity against DPPH radicals (IC50 = 88.33 ± 3.53 ppm). These were higher than ethanol with other concentrations. However, various things need to be considered when using this solvent given the high water content in the solvent.

In the present work, the phenol-sulfuric acid method and the 3,5-dinitrosalicylic acid (DNS) method were developed with the aim to quantitatively analyze total sugars and reducing sugars, respectively. In regard with the phenol-sulfuric acid assay, 1.0 mL of sample was treated with 1.0 mL of 5% phenol, 5.0 mL of concentrated H₂SO₄ and measured at 485 nm, with the linearity range of 10–100 ppm for total sugars. The DNS method was performed on 2.0 mL of sample, using 1.5 mL of DNS at 80 °C for 10 minutes and measured at 510 nm, with the linearity range of 50–400 ppm for reducing sugars. The sugar contents of white dragon fruit-derived sugar-samples (extracted from species in Binh Thuan province, Vietnam) were also estimated by the above measured methods, exhibiting the total sugars of above 90% and the reducing sugars of above 5%. The methods were well-performed with the acceptable relative standard deviations of repeatability in accordance with the Association of Official Analytical Chemists (AOAC).

The purpose of this research to explore the impact of parental involvement on the academic achievement of students at Crescent International School and to determine whether the demographic variable of parents has an effect on their involvement in their children's education. In addition, the study sought to examine what existing literature review found on the relation between parental involvement and children's academic achievement. The present study was carried out at Crescent International School in Bangkok, Thailand. The responses of 12 parents, whose children are enrolled in secondary level, were taken as samples for the current study. The Intensity Sampling Technique was used in this research. A questionnaire about demographics of parents was distributed and interviews were conducted to assess the level of parent involvement. To find out student achievement level, the students results were used. The qualitative method was used to gauge the impact of parental involvement on students' academic achievement. The results revealed that parental income level has no impact on the level of involvement in their children's education. However, educational level, age, employment and marital status of the parents had greater impact on parental involvement. The main findings of this research indicated that students with highly involved parents had better academic performance and higher test scores in all the subjects compared to students whose parents were not involved in their education. the findings, suggested that parents should grow more awareness on the importance of visiting and supporting their children in school. It was also recommended that parents should take an active role in assisting their children's education at school and at home since they are the first teachers of their children.

These days, the third worlds countries such as Egypt are facing a hug challenge toward energy production. Energy crisis is the most critical issue facing these developing countries. In the recent couple of years Egypt has experienced a serious shortage in the power supply which affect negatively the industry sector as well as the residential sector due to the shortage of natural gas production and fossil fuel which prevented the government from providing the basic needs of Energy to the community. Moreover, it affects negatively the developing of this country and building a new mega projects. Renewable energy sources can be an extraordinary method to tackle the energy issue in Egypt, the increasing of energy costs and decreasing of fissile fuel production helps in decreasing the gap between the cost of generating Energy from renewables and fissile fuel. It is important to set up public Egyptian facilities based on renewable energy as metro stations instead of relying upon fossil fuel as a main source of power. Generating electricity from piezoelectric cells to power metro station is a sustainable solution for the environment, economy, and social needs. Using piezoelectric cells in high density projects helps in creating energy self-sustain projects, people will start to produce energy from walking throughout the facility. The aim of this research is to highlight the importance of replacing ceramic and granite tiles with sustainable piezoelectric tiles, which will create a self-sustain project by redesign an interior space of public facilities. Designing the flooring tiles that integrate piezoelectric cells produce a useful amount of energy for electrifying public facilities using the visitor's high population density. The research started to analyses projects that replaced regular tiles with piezoelectric tiles to understand the objectives and constrains of using this sustainable building material in Egyptian public facilities.

Urban Heat Island (UHI) is one of the most serious difficulties that humans have faced in the twenty-first century resulted due to urbanization and industrialization. The main causes of UHI are the vast amounts of heat produced by urban structures, which solar energy should be used and re-radiated as well as anthropogenic heat sources. The two heat sources cause an urban area's temperature to rise in comparison to its surrounding areas, which refers to a phenomenon of the urban heat islands. Large cities and diverse economic activities face even more serious difficulties. This paper defined the concept and types of UHIs. This paper explained a comprehensive review of the phenomenon of UHI from its first appearance with regard to causing factors, its influences on people's lives and the urban environments, and widely used data for measuring and evaluating the intensity of UHIs. The finding of most studies mentioned that UHI values are different from city to city based on land-use changes. It is revealed that an increasing trend occurred mainly because expand in built-up areas and a reduction in green cover. Also, a number of studies showed that the UHI intensity was low during summer afternoons and high during winter nights in many places around the world.

Geothermal or earth's heat is a thermal energy dominant countries have been located along the plate boundaries where volcanism or earthquakes are concentrated. One of the world largest geothermal activities has been found in the region of Pacific Ring of Fire/ROF. More than 40% geothermal energy resources are stored in that region. The Ring of Fire that rims the Pacific Ocean and is bounded by Japan, the Philippines, the Aleutian Islands, North America, Central America, and South America etc. United States is still global geothermal energy leader which are located in that volcanic belt, Philippines is second-largest geothermal energy producer in the world, Japan is currently large geothermal power producer in the world, Indonesia that has around 29000 MW of untapped geothermal power. Most of the countries of that region have been stored huge geothermal energy resources. The above explanation of geothermal energy resources of Pacific Ring of Fire which working as a home country of geothermal resources in the world.

In recent years, under the double pressure of energy exhaustion and environmental deterioration, the development of electric vehicles has become the major development trend of the automotive industry in the future. This paper discusses the problem of abandoned batteries caused by the limited life of a large number of batteries with the prosperity of new energy vehicle industry. This paper lists and analyzes the different characteristics of batteries commonly used by three new energy vehicles in the market :(1) lead-acid batteries will not leak in the use process due to tight sealing, but their use cycle is very short. (2) The production of nickel metal hydride battery is relatively mature, its production cost is low, and compared with lithium electronic battery is safer. (3) Lithium-ion batteries are made of non-toxic materials, which makes them known as "green batteries". However, they are expensive to make and have poor compatibility with other batteries. Because discarded batteries pose a threat to human health and environmental sustainability, lithium-ion batteries may overheat and fire when exposed to high temperatures or when penetrated, releasing carbon monoxide and hydrogen cyanide that can be very harmful to human health. In addition, waste batteries will also cause water pollution and inhibit the growth and reproduction of aquatic organisms and other potential dangers. Therefore, it is necessary to recycle it efficiently. This paper then introduces the advantages of three recycling methods: step utilization and recovery, ultrasonic recovery and sodium ion battery. These recycling methods can maximize the reuse efficiency of waste batteries. This paper expects to find a better way to recycle waste batteries to solve the potential problems of improper disposal of waste batteries and reduce the environmental hazards of waste batteries.

On behalf of the organizing committee, I would like to express our gratitude for your participation in the 3rd International Seminar on Earth Science and Technology or ISEST.

As the name implies, ISEST has been held 3 times, including this time. The first ISEST was held in December 2021, under the grasp of COVID-19 pandemic. During that time, all the presentation was held online. The second ISEST was held in March 2023. Although the condition is more relaxed, but many people still cautious, hence the 2nd ISEST was held in hybrid mode. This year, the situation is much better, thus we decided that the seminar will be fully offline. However, due to some circumstances, several presenters cannot join us here and decided to deliver their presentation online.

The main theme of the 3^rd ISEST is "Navigating the changing world through earth sciences and technology". The theme emphasizes the adaptable approach to earth related problems, from natural resources utilization to natural disaster management. The main theme is divided into 4 topics, which are Solid Earth Sciences, Ocean Sciences, Atmospheric Sciences, and Interdisciplinary Earth Science and Technology. We also have two joint special sessions. The first one today is the Blue Economy special session collaborated with the Ministry of Maritime Affairs and Fisheries. In the next day we will have the second special session of Disaster Risk Financing, in collaboration with Directorate General of Budget Financing and Risk Management of Ministry of Finance.

List of Executive Committee, Special Session Coordinator, Editorial Board, International Reviewer, National Reviewer, Steering Committee, Keynote Speakers and Invited Speakers are available in this Pdf.

All papers published in this volume have been reviewed through processes administered by the Editors. Reviews were conducted by expert referees to the professional and scientific standards expected of a proceedings journal published by IOP Publishing.

• Type of peer review: Single Anonymous

• Conference submission management system: Morressier

• Number of submissions received: 51

• Number of submissions sent for review: 45

• Number of submissions accepted: 45

• Acceptance Rate (Submissions Accepted / Submissions Received × 100): 88.2

• Average number of reviews per paper: 1

• Total number of reviewers involved: 24

• Contact person for queries:

Name: Brian Bramanto, Ph.D.

Email: brian.bramanto@itb.ac.id

Affiliation: Institut Teknologi Bandung

In recent years, the BMKG (Indonesian Meteorological, Climatological, and Geophysical Agency) has provided premium climate services to PT Berau Coal, including 10-day and monthly rainfall forecasts. These services are crucial for mining operations in preparing work plans, as rainfall can make roads at the mining site slippery, leading to reduced effective working hours, increased pump operating hours, and higher fuel costs. This study evaluates the performance of monthly rainfall predictions for three mining sites (Sambarata, Lati, and Binungan) over the period 2005-2023, based on the availability of rainfall observation data at the mining sites, using the RMSE and Percent of Correct (PoC) methods. The analysis shows that for a lead time of one (six) month, i.e., a forecast given one (six) month in advance, the average RMSE is 94 (95) mm/month. The highest error is observed in January, at 140 (144) mm/month, while the lowest error occurs in August, at 65 (69) mm/month. The PoC values range from 42% to 89%. These results indicate that the climate service forecasts have reasonably good accuracy and can be used as a reference in decision-making, although potential errors, as indicated by the RMSE values, should still be considered.

Model simulations for Borneo suggest potential difficulties in capturing the variability of rainfall on regional scales due to complex topography and climate interactions. This study utilizes a high-resolution Conformal Cubic Atmospheric Model (CCAM) to address the impacts of climate change on a regional scale over Borneo by analyzing key parameters such as precipitation, surface temperature, mean sea level pressure, and relative humidity over Borneo for the near future (2023-2033). We also found that the MAM (March-April-May) and SON (September-October-November) seasons show higher rainfall than the DJF (December-January-February) season. Meanwhile, relative humidity tends to decrease in the future compared to previous years. Mean sea level pressure (MSLP) tends to increase over the border of Indonesia and Malaysia in the JJA (June-July-August) season but decreases over southern Borneo in the MAM (March-April-May) and SON (September-October-November) seasons. There is a noticeable increase in temperature from the MAM (March-April-May) to SON (September-October-November) season in the east-south region. However, further research is required to validate these projections.

Sea-breeze circulation is known to well develop during the dry season months of July to September over the northern coast of West Java. On the other hand, compared to other areas in Java Island, strong convection and heavy rainfall more frequently occur in the most western part of the Island during the dry season. This study investigates the relationships between sea-breeze development and propagation, and the convections around this region. By analyzing surface winds and relative humidity observed over two sites near Jakarta, sea-breeze intrusion times and the speed of sea-breeze front propagation can be estimated. It is found that on average, sea-breeze develops around 09:00 LT and propagates at a speed of about 1.44 m/s near over the coastal plain. However, there is also variation in the sea-breeze propagation speed ranging from 0.48 m/s to 4.69 m/s. Meanwhile, convective activites are identified from satellite imageries. Further analyses reveal that faster sea-breeze propagation tend to be associated with deeper and larger convections, compared to the slower ones. This indicates that sea-breeze propagates faster under more unstable atmosphere, consistent with previous studies. Impacts of collisions of sea-breezes developed over different coastlines have not been thoroughly analyzed in this study.